The T. K. Sidey Medal is awarded at irregular intervals for outstanding scientific research concerning electromagnetic radiation. Such research may include interaction with matter, its impact on living organisms, its use in communications or its application in any other manner beneficial to human welfare. While the original terms of the award pertained to solar electromagnetic radiation in particular, the Society takes the broad view that the work may be related to electromagnetic radiation of any wavelength, and, from time to time, it may award the medal for research involving radiation of any kind.